In humans, the foramen spinosum (FS) is located within the sphenoid bone and transmits the middle meningeal artery (MMA). In species that evolutionarily predate humans, the FS exists within the temporal bone, the sphenosquamosal suture, or is absent altogether. It is therefore thought that, during the course of human evolution, the ossification of the posterior aspect of the greater wing of the sphenoid progressively developed around the MMA. The report documents the occurrence of a bilateral duplication of the FS in a male human skull. The report also discusses the clinical and developmental/anthropological significance. Because the foramen spinosum is utilized as a landmark for various surgical procedures involving the middle cranial fossa, the bilateral duplication of the foramen may be disorienting to the surgeon. Similarly, the dynamics of blood flow may be altered due to the bilateral bifurcation of the MMA. Because of the developmental significance of the FS, the occurrence of a bilateral duplication also has important anthropological implications.
Zdilla MJ, Jillian M Laslo JM, Cyrus LM (2014) Bilateral Duplication of the Foramen Spinosum: A Case Report with Clinical and Developmental Implications . Anat Physiol 4:162.